I bought a little aquarium for my grandaughter for Christmas. Mom and dad bought her a couple of small glofish for it, and apparently the filter sucked them up. 
So, tonight I bought a heater so they can buy larger tropical fish. I guess my question is: is this something that happens often? She’s only 8 so it was pretty traumatic.
We don’t have a lot of experience with this sort of thing so shopping for equipment is daunting.
Fish getting sucked into a filter should not happen often. Or at all. Assuming your granddaughter’s aquarium had an external filtration system, the intake for it should have had a small cage-like structure on the end to prevent plant material and fish from getting drawn into it.
How big is the aquarium? Most smaller aquaria (say, less than 50 gallons or so) can work just fine with a biological filter, which draws tank water down through a gravel bed (or other filter media) with no separate impeller-fed filter chamber. Even a larger tank can get by with a biological filter with little problem.
It’s 2 1/2 gallons. They were originally going to get a Beta, but my grandaughter wanted more than one fish. The aquarium was a all in one starter kit. Apparently where they bought the fish only had very small non-tropical fish.
I have personally not seen the tank set up. My daughter did comment on the lack of screening over the filter tube.
Oops, it’s a 31/2 gallon.
I’m sorry to say this but a 3.5 gal tank isn’t big enough for fish, really. A betta, maybe, but even they should have more room. They CAN live in small spaces, but so can humans (think jail cell). It’s not a good existence. Shrimp might do well - you can get all sorts of fancy tiny shrimp.
Definitely do not do goldfish. They are dirty fish and grow very quickly.
You can get foam covers for the intake of the filter that will keep anything small from being sucked in, and also provide a surface for the good bacteria to grow on. Aquariums have a pretty intricate biological cycle that takes some time to get going, but will keep the water healthy for the Fish once it’s stable. However, the smaller the aquarium the harder it is to keep stable, I’m afraid.
For happy fish and a happy kid, a 10 gal is the way to go if you want more than a single betta or some fancy shrimp.
And a 20 is even better, and not that much larger.
My parents (former fish breeders and long-time aquarium keepers) wouldn’t bother with anything less than a 20 gallon tank. And they typically went with under-gravel filters as well, and some few plants and algae eating fish.
Go to Goodwill. They often have aquariums there, ten gallons and up.
Is the biological filter mentioned above an under gravel filter? Those are a pain in the neck to clean with all the fish poop sucked into the substrate.
Where are you? If you are in Central Arkansas, I’ll give her a ten gallon.
They’re no problem to clean with a siphon and bucket. Just don’t draw so much water into the siphon that you actually drink some of it. You would not enjoy it. Trust me on this.
Not an undergravel, then.
Not sure what you’re talking about, but I’ll clarify. IMO, a biological undergravel filter is the easiest, simplest, and cheapest filtration system for beginners. Cleaning them just takes a siphon which any pet store sells for not much money, and the gravel doesn’t have to be cleaned more than every 2-3 months or so. It can be a bit of a PITA carrying a bucket full of fish poopy water to dump, but the garden will thank you for it. And as long as you limit the water change to 30-50%, you shouldn’t have any other problems.
In my experience, the only time an undergravel system really gets to be a problem is if you have a very tall tank (say, 4’ or more) and have short arms (or generally short stature). Then reach becomes an issue.
There winds up being a lot of fish poop under the gravel. We must have had different experiences cleaning them.
I have a gravel bed that’s about 3-4” deep, and I plunge the siphon all the way through the gravel to the filter grids, which sucks out all the poop in a 2” diameter (the diameter of the siphon mouth). I just keep moving it around, plunging it into the gravel and sucking up all the waste, letting the gravel fall back down onto the bottom of the tank. Granted, it doesn’t get it all out, but you want to leave some, because otherwise the tank will be sterile and you’ll lose the biological action that makes the whole thing work.
Without seeing your setup or knowing what kind of filter you have, I’ll say that IME, it’s a whole lot more common for a fish to die and then get sucked into the filter as opposed to the filter killing it.
Those little glofish should have no problem staying away from it.
What do you mean when you refer to ‘tropical fish’? Leaving out the size issue that others brought up, saltwater fish (which is what I think of when I hear ‘tropical fish’) is practically a different hobby.
But if you’re leaning towards that, I/we can help. I had a freshwater tank up and running for probably 10 years before I switched it over to saltwater 5 or 6 years back.
Excellent point that had not occurred to me, but way more logical.
There are, of course, small freshwater tropical fish.
That would work very well, I stand corrected.
Which is why I asked the OP what they were referring to.
I guess they are going to do a Beta. My grandson gave her some of his ( supposed to be feeder goldfish for his turtle umm nother story) I told them that they are way too big for that tank. Anyway, the glow fish were very tiny. I am going to put some filter sponge over the filter inlet. I really don’t think they died first, like fry they just couldn’t swim strongly enough.
According to my daughter the only larger fish available as in larger than fry required heat though not salt water.
We are in Michigan, I do appreciate the offer. It was very kind.
Thanks. By all means check Goodwill and like stores.
I recommend some live plants to maintain water quality, improve appearance and provide a refuge for fish.
Hornwort (floating) and jungle val are easy to grow with low to moderate supplemental light.